Recent studies have shown that chronic mentally ill adults living in the community are at elevated behavioral risk for contracting HIV infection, and that HIV seroprevalence is already high among the chronic mentally ill. Vulnerability to HIV risk behavior in this population is associated with characteristics of severe mental illness (often including poor social problem solving, impulsivity, sexual acting out, and co-existing substance use); risk-producing social interaction patterns (including having transient social and sexual relationships, vulnerability to exploitation and coercion, and relationships with others who share similar problems); and the urban inner-city environment where many chronic mentally ill persons live, areas where HIV, STD's, and drug abuse are increasingly common. A one-year period of support for pilot work resulted in studies that have established risk behavior characteristics in a sample of ethnically-diverse chronic mentally ill adult men and women and that have permitted opportunities to pilot test risk behavior assessment measures. This renewal application request support to now begin a controlled trial of a cognitive-behavioral HIV risk reduction intervention based on social learning principles already successfully used in other "community living" approaches for the chronic mentally ill. From the patient population of urban mental health clinics, 200 men and 200 women who meet criteria for high HIV risk will be recruited. All participants will be assessed using a battery of measures of risk knowledge and intentions; cognitive and behavioral skills pertinent to risk reduction change; sexual and substance use behavior; and presence of STD's. Two hundred participants will be randomly assigned to a 10- session group intervention program which includes risk education, behavior change planning, training in cognitive and behavioral risk reduction skills, and reinforcement of change efforts. The other 200 participants will attend a comparison intervention focused on health behavior change in areas unrelated to AIDS. All participants will be reassessed at postintervention and through an 18-month follow-up to determine intervention effectiveness. It is hypothesized that HIV intervention participants will exhibit increased risk knowledge, improved behavior and cognitive risk reduction skills, less frequent high-risk behavior, and lower rates of STD's at follow-up. The intent of this work is to develop and evaluate an HIV prevention model that can be practically implemented by community mental health programs which serve the chronic mentally ill.